Airbag for shoes

ABSTRACT

An airbag for shoes has a plurality of elastically compressible cylindrical cushion members which are interconnected in a predetermined array by a connecting plate. The cushion members/connecting plate combination is encapsulated in a casing. The cushion members, connecting plate and casing are joined together to form an integral unit. The cushion members have a spiral groove formed in their outer surface which increases their compressibility during the initial phase of compression.

BACKGROUND AND SUMMARY OF THE INVENTION

This invention relates to an airbag for shoes and particularly to anairbag which contains mechanical cushion members to provide long lifeand to provide support if the airbag should become punctured.

Airbags are commonly placed in the soles of sneakers to cushion thebottoms of the user's feet from the impact of running or walking.However, airbags do not provide sufficient cushioning for high loads andcan lose their cushioning effect after repeated use. In co-pendingapplication Ser. No. 29149621, now U.S. Design Patent D460854resiliently flexible, cylindrical cushion members are placed in anairbag at spaced-apart locations. The cushion members are held in theirdesired locations by a stiffer flexible connecting plate, and thecushion members and the connecting plate are enclosed in a flexiblecasing. The cushion member, connecting plate and casing, are all madefrom a plastic material and are cast together to form an integral unit.While this type of airbag is an improvement over the previous airbags,if the cushion members are stiff enough to give adequate cushioning athigh loads, they are too stiff at light loads or during the initialstages of loading.

The airbag of the subject invention overcomes this problem by placingspiral grooves around the periphery of the cushion members to give thema spring-like structure. This allows the cushion members to be lessstiff under light or initial loading and still have sufficient stiffnessto provide the necessary cushioning effect at higher levels of loading.

The foregoing and other objectives, features, and advantages of theinvention will be more readily understood upon consideration of thefollowing detailed description of the invention, taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a perspective view of an airbag for shoes embodying thesubject invention.

FIG. 2 is a cross-sectional view taken on line 2—2 of FIG. 2.

FIG. 3 is a cross-sectional view similar to FIG. 2, showing anotherembodiment of the invention.

FIG. 4 is a plan view of the airbag shown in FIGS. 1 and 2.

FIG. 5 is a plan view of the airbag shown in FIG. 3.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Referring to FIGS. 1, 2 and 4 of the drawings, a first preferredembodiment of an airbag 10 includes a plurality of individual cushionmembers 12. The cushion members are elastically compressible and aremade from a material whose resistance to compression becomes greater asit becomes more compressed. In this preferred embodiment the cushionmembers are made from a soft plastic material such as polyvinyl chlorideor polyurethane, although any elastically compressible material wouldwork. The cushion members are cylindrical and have a spiral groove 14formed in their outer surface. The cushion members illustrated arecircular in cross-section but other cross-sectional shapes would work aswell. The cushion members illustrated are annular with an open center16, but they also could be solid.

In the embodiment illustrated there are four cushion members 12 butthere could be more or less. The cushion members are shown as beingspaced apart from one another at the corners of a rectangle, but anypattern which places them evenly over the airbag would suffice. In orderto maintain the cushion members in the desired relationship relative toone another they are attached to a semi-rigid connecting plate 18. Whilethe connecting plate needs to be harder and less flexible than thecushion members, it could be made from the same or a similar material.The connecting plate has projecting annular fingers 20 which fit intonotches 22 located in the bottoms of the cushion members. Because thecushion members and connecting plate are made from similar materials,one can be placed in the mold when the other is being cast, which willcause them to be integrally joined. As a result, the connecting platesecurely holds the cushion members in place. The cushionmember/connecting plate combination is encapsulated in a casing 26. Thecasing is formed from a relatively soft plastic material and isair-tight. The casing is cast around the assembled cushionmember/connecting plate combination and thus is integrally bonded to it.In addition, the casing extends into both sides of the open centers 16of the cushion members to form an even better bond between them.

In operation, the air-tight casing 26 forms an airbag which is insertedinto the sole of a shoe (not shown) in the conventional manner. Thecushion members 12 add to the airbag's resistance to deflection andprovide an independent source of cushioning in case the airbag becomespunctured. In addition, the solid cushion members lose little of theircushioning ability after repeated use. Unlike conventional airbagshaving cushion members located in them, the cushion members of thesubject invention provide less cushioning effect during their initialcompression. This is because the projecting spiral element 24 collapsesinto the spiral groove 14 as the cushion member is initially compressed.However, once the spiral element has completely collapsed against itselfthe compressibility of the cushion member increases and becomes similarto the compressibility of a cushion member without a spiral groove.

In an alternative embodiment 28 of the invention, shown in FIGS. 3 and5, the cushion members 12 are replaced by spiral coil springs 30. Thesprings 30 typically would be metal but they could be made from othermaterials as well. In this embodiment the fingers 20 of the connectionplate 18 fit over the bottom coils 32 of the springs. The top and bottomcoils of a spring are perpendicular to the center line of the springrather than spiral like the intermediate coils 34. Thus the casing 26fits snugly against the top and bottom coils and projects into thecentral openings 36 of the springs. Otherwise this embodiment of thesubject invention is the same as the embodiment shown in FIGS. 1, 2 and4. However, the casing and connection plate do not bond to the spring 30in the same manner as they do to the cushion members 12.

The terms and expressions which have been employed in the foregoingspecification are used therein as terms of description and not oflimitation, and there is no intention, in the use of such terms andexpressions, of excluding equivalents of the features shown anddescribed or portions thereof, it being recognized that the scope of theinvention is defined and limited only by the claims which follow.

What is claimed is:
 1. An airbag comprising: (a) a plurality ofelastically compressible cushion members; (b) a connecting plate whichis attached to said cushion members and holds said cushion members in adefined array; (c) an air-tight casing which surrounds said cushionmembers and said connecting plate; and (d) wherein said cushion membersare cylindrical and have a spiral groove defined therein to provide aspring-like structure.
 2. The airbag of claim 1 wherein said cushionmembers and said connecting plate are integrally joined.
 3. The airbagof claim 2 wherein said cushion members, said connecting plate and saidcasing are integrally joined.
 4. The airbag of claim 3 wherein saidcushion members, said connecting plate and said casing are made from asimilar plastic material.
 5. The airbag of claim 1 wherein said cushionmembers are annular with open centers.
 6. The airbag of claim 5 whereinsaid casing extends partially into said open centers.